1. Field of the Invention
The present invention relates to a chemically amplified photoresist composition. The invention further relates to a photosensitive polymer to be used in the photoresist composition, which polymer has a backbone structure containing an alicyclic compound that increases the resistance of the photoresist composition to dry etching. The photoresist compositions of the present invention are suitable for use with an ArF excimer laser.
2. Description of the Related Art
Current semiconductor devices are highly integrated and complicated to manufacture, requiring a very fine resist pattern. Further, as the capacity of a semiconductor device increases to exceed 1 Gbit, a pattern size having a design rule less than 0.2 .mu.m is required. Accordingly, there are limitations to using conventional photoresists that are developed with a KrF excimer laser (248 nm). Thus, a new photoresist material capable of being developed by an ArF excimer laser (193 nm) has been produced for use in a photolithography process.
Methacrylate polymers are generally used as the resist material in photolithography processes for use with the ArF excimer laser. However, such polymers have a very weak resistance to dry etching. To increase resistance to dry etching, a polymer having a backbone composed of an alicyclic compound such as an isobonyl group, an adamantyl group or a tricyclodecanyl group is used. These conventional polymers, however still exhibit weak resistance to dry etching.